RE: Accessing scsi based external storage

-----Original Message-----
From: plug-discuss-admin@lists.plug.phoenix.az.us on behalf of Austin Godber
Sent: Mon 10/4/2004 12:53 PM
To: plug-discuss@lists.plug.phoenix.az.us
Subject: Re: Accessing scsi based external storage

Sanjay Darisi wrote:
> How do I know the limit on scsi devices in FC1?? Only when I try to access it or is there any info page describing the limit in FC1??
>
> I don't see scsi card talking during bootup. But, I found out that there is a web based configuration page for hte storage box. The only RAID level that I can setup on that is 0, which goes upto 1250GB. If I set this up and FC1 has that limit of 1TB then I'm not in a good situation, do I? The manual of the storage box says it can support upto 2TB (8 bays) and I donno how, the maximum that I can see is with RAID 0 (i.e., 1.25TB). Does FC2 with 2.6 kernel has any limit like this on block devices??
>
> Sanjay.

I am sorry Sanjay. I should pay more attention. The RAID array is a
completely seprate device and doesn't reboot with the server? Have you
created the RAID 0 array then and then booted up and see what you get
from the scsi bus in dmesg?

Does the controller and also the external storage show up on the scsi
bus? cat /proc/scsi/scsi

The limitation in RHEL 2.1 was not necessarily in the kernel. I think
it was actually in some of the userspace applications like fdisk or df
... maybe in the kernel but I don't think the limitation is inherent to
the 2.4 kernel. Once the raid array was built I would see some huge
negative size when I did df IIRC. If your disk size reads right once
you see it the I wouldn't worry about it.

Austin
----------------------

You are correct austin, I was able to go to the setup of hte scsi card. The reason I couldn't see any scsi card related setup info during bootup was the scsi card was connected to the PCI bus using a PCI bridge. It was a Dell GX150 machine and it has got a PCI bridge thing, scsi card is connected to it. Bios couldn't see it and used to give
Plug and Play error, press F1 to continue and F2 for setup

I suspected something wrong, opened up the box and realized the bridge thing. I plugged the card into another machine and it boots up well. I can go to the setup of the card too.

As Alan said, the whole storage device is attached to /dev/sda (I configured RAID 0 with 5 drives). I saw the device with 1250.2 GB capacity. So, I don't think 1TB limit exists in FC1, though during bootup I saw a message

blk queue: somenumber limit: 1TB (the number is displayed in MB) mask: (some number of fs)

after recognizing the scsi device. I was frightened that there is this limit. But, fdisk recognized it as 1250GB and I've created only one partition of 1.25TB, just to test. I haven't got a chance to create filesystem and play around 'cos the external storage system proved to be a defective one and powers down by itself very frequently.

I have a question, there is a serial cable that comes with that device. I have connected it to the host computer and I donno how to read from that. Is there any hyper terminal program that I have to use??

Sanjay.